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 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.lang;

/**
 * The {@code Short} class wraps a value of primitive type {@code
 * short} in an object.  An object of type {@code Short} contains a
 * single field whose type is {@code short}.
 *
 * <p>In addition, this class provides several methods for converting
 * a {@code short} to a {@code String} and a {@code String} to a
 * {@code short}, as well as other constants and methods useful when
 * dealing with a {@code short}.
 *
 * @author Nakul Saraiya
 * @author Joseph D. Darcy
 * @see java.lang.Number
 * @since JDK1.1
 */
public final class Short extends Number implements Comparable<Short> {

  /**
   * A constant holding the minimum value a {@code short} can
   * have, -2<sup>15</sup>.
   */
  public static final short MIN_VALUE = -32768;

  /**
   * A constant holding the maximum value a {@code short} can
   * have, 2<sup>15</sup>-1.
   */
  public static final short MAX_VALUE = 32767;

  /**
   * The {@code Class} instance representing the primitive type
   * {@code short}.
   */
  @SuppressWarnings("unchecked")
  public static final Class<Short> TYPE = (Class<Short>) Class.getPrimitiveClass("short");

  /**
   * Returns a new {@code String} object representing the
   * specified {@code short}. The radix is assumed to be 10.
   *
   * @param s the {@code short} to be converted
   * @return the string representation of the specified {@code short}
   * @see java.lang.Integer#toString(int)
   */
  public static String toString(short s) {
    return Integer.toString((int) s, 10);
  }

  /**
   * Parses the string argument as a signed {@code short} in the
   * radix specified by the second argument. The characters in the
   * string must all be digits, of the specified radix (as
   * determined by whether {@link java.lang.Character#digit(char,
   * int)} returns a nonnegative value) except that the first
   * character may be an ASCII minus sign {@code '-'}
   * ({@code '\u005Cu002D'}) to indicate a negative value or an
   * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
   * indicate a positive value.  The resulting {@code short} value
   * is returned.
   *
   * <p>An exception of type {@code NumberFormatException} is
   * thrown if any of the following situations occurs:
   * <ul>
   * <li> The first argument is {@code null} or is a string of
   * length zero.
   *
   * <li> The radix is either smaller than {@link
   * java.lang.Character#MIN_RADIX} or larger than {@link
   * java.lang.Character#MAX_RADIX}.
   *
   * <li> Any character of the string is not a digit of the
   * specified radix, except that the first character may be a minus
   * sign {@code '-'} ({@code '\u005Cu002D'}) or plus sign
   * {@code '+'} ({@code '\u005Cu002B'}) provided that the
   * string is longer than length 1.
   *
   * <li> The value represented by the string is not a value of type
   * {@code short}.
   * </ul>
   *
   * @param s the {@code String} containing the {@code short} representation to be parsed
   * @param radix the radix to be used while parsing {@code s}
   * @return the {@code short} represented by the string argument in the specified radix.
   * @throws NumberFormatException If the {@code String} does not contain a parsable {@code short}.
   */
  public static short parseShort(String s, int radix)
      throws NumberFormatException {
    int i = Integer.parseInt(s, radix);
    if (i < MIN_VALUE || i > MAX_VALUE) {
      throw new NumberFormatException(
          "Value out of range. Value:\"" + s + "\" Radix:" + radix);
    }
    return (short) i;
  }

  /**
   * Parses the string argument as a signed decimal {@code
   * short}. The characters in the string must all be decimal
   * digits, except that the first character may be an ASCII minus
   * sign {@code '-'} ({@code '\u005Cu002D'}) to indicate a
   * negative value or an ASCII plus sign {@code '+'}
   * ({@code '\u005Cu002B'}) to indicate a positive value.  The
   * resulting {@code short} value is returned, exactly as if the
   * argument and the radix 10 were given as arguments to the {@link
   * #parseShort(java.lang.String, int)} method.
   *
   * @param s a {@code String} containing the {@code short} representation to be parsed
   * @return the {@code short} value represented by the argument in decimal.
   * @throws NumberFormatException If the string does not contain a parsable {@code short}.
   */
  public static short parseShort(String s) throws NumberFormatException {
    return parseShort(s, 10);
  }

  /**
   * Returns a {@code Short} object holding the value
   * extracted from the specified {@code String} when parsed
   * with the radix given by the second argument. The first argument
   * is interpreted as representing a signed {@code short} in
   * the radix specified by the second argument, exactly as if the
   * argument were given to the {@link #parseShort(java.lang.String,
   * int)} method. The result is a {@code Short} object that
   * represents the {@code short} value specified by the string.
   *
   * <p>In other words, this method returns a {@code Short} object
   * equal to the value of:
   *
   * <blockquote>
   * {@code new Short(Short.parseShort(s, radix))}
   * </blockquote>
   *
   * @param s the string to be parsed
   * @param radix the radix to be used in interpreting {@code s}
   * @return a {@code Short} object holding the value represented by the string argument in the
   * specified radix.
   * @throws NumberFormatException If the {@code String} does not contain a parsable {@code short}.
   */
  public static Short valueOf(String s, int radix)
      throws NumberFormatException {
    return valueOf(parseShort(s, radix));
  }

  /**
   * Returns a {@code Short} object holding the
   * value given by the specified {@code String}. The argument
   * is interpreted as representing a signed decimal
   * {@code short}, exactly as if the argument were given to
   * the {@link #parseShort(java.lang.String)} method. The result is
   * a {@code Short} object that represents the
   * {@code short} value specified by the string.
   *
   * <p>In other words, this method returns a {@code Short} object
   * equal to the value of:
   *
   * <blockquote>
   * {@code new Short(Short.parseShort(s))}
   * </blockquote>
   *
   * @param s the string to be parsed
   * @return a {@code Short} object holding the value represented by the string argument
   * @throws NumberFormatException If the {@code String} does not contain a parsable {@code short}.
   */
  public static Short valueOf(String s) throws NumberFormatException {
    return valueOf(s, 10);
  }

  private static class ShortCache {

    private ShortCache() {
    }

    static final Short cache[] = new Short[-(-128) + 127 + 1];

    static {
      for (int i = 0; i < cache.length; i++) {
        cache[i] = new Short((short) (i - 128));
      }
    }
  }

  /**
   * Returns a {@code Short} instance representing the specified
   * {@code short} value.
   * If a new {@code Short} instance is not required, this method
   * should generally be used in preference to the constructor
   * {@link #Short(short)}, as this method is likely to yield
   * significantly better space and time performance by caching
   * frequently requested values.
   *
   * This method will always cache values in the range -128 to 127,
   * inclusive, and may cache other values outside of this range.
   *
   * @param s a short value.
   * @return a {@code Short} instance representing {@code s}.
   * @since 1.5
   */
  public static Short valueOf(short s) {
    final int offset = 128;
    int sAsInt = s;
    if (sAsInt >= -128 && sAsInt <= 127) { // must cache
      return ShortCache.cache[sAsInt + offset];
    }
    return new Short(s);
  }

  /**
   * Decodes a {@code String} into a {@code Short}.
   * Accepts decimal, hexadecimal, and octal numbers given by
   * the following grammar:
   *
   * <blockquote>
   * <dl>
   * <dt><i>DecodableString:</i>
   * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
   * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
   * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
   * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
   * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
   *
   * <dt><i>Sign:</i>
   * <dd>{@code -}
   * <dd>{@code +}
   * </dl>
   * </blockquote>
   *
   * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
   * are as defined in section 3.10.1 of
   * <cite>The Java&trade; Language Specification</cite>,
   * except that underscores are not accepted between digits.
   *
   * <p>The sequence of characters following an optional
   * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
   * "{@code #}", or leading zero) is parsed as by the {@code
   * Short.parseShort} method with the indicated radix (10, 16, or
   * 8).  This sequence of characters must represent a positive
   * value or a {@link NumberFormatException} will be thrown.  The
   * result is negated if first character of the specified {@code
   * String} is the minus sign.  No whitespace characters are
   * permitted in the {@code String}.
   *
   * @param nm the {@code String} to decode.
   * @return a {@code Short} object holding the {@code short} value represented by {@code nm}
   * @throws NumberFormatException if the {@code String} does not contain a parsable {@code short}.
   * @see java.lang.Short#parseShort(java.lang.String, int)
   */
  public static Short decode(String nm) throws NumberFormatException {
    int i = Integer.decode(nm);
    if (i < MIN_VALUE || i > MAX_VALUE) {
      throw new NumberFormatException(
          "Value " + i + " out of range from input " + nm);
    }
    return valueOf((short) i);
  }

  /**
   * The value of the {@code Short}.
   *
   * @serial
   */
  private final short value;

  /**
   * Constructs a newly allocated {@code Short} object that
   * represents the specified {@code short} value.
   *
   * @param value the value to be represented by the {@code Short}.
   */
  public Short(short value) {
    this.value = value;
  }

  /**
   * Constructs a newly allocated {@code Short} object that
   * represents the {@code short} value indicated by the
   * {@code String} parameter. The string is converted to a
   * {@code short} value in exactly the manner used by the
   * {@code parseShort} method for radix 10.
   *
   * @param s the {@code String} to be converted to a {@code Short}
   * @throws NumberFormatException If the {@code String} does not contain a parsable {@code short}.
   * @see java.lang.Short#parseShort(java.lang.String, int)
   */
  public Short(String s) throws NumberFormatException {
    this.value = parseShort(s, 10);
  }

  /**
   * Returns the value of this {@code Short} as a {@code byte} after
   * a narrowing primitive conversion.
   *
   * @jls 5.1.3 Narrowing Primitive Conversions
   */
  public byte byteValue() {
    return (byte) value;
  }

  /**
   * Returns the value of this {@code Short} as a
   * {@code short}.
   */
  public short shortValue() {
    return value;
  }

  /**
   * Returns the value of this {@code Short} as an {@code int} after
   * a widening primitive conversion.
   *
   * @jls 5.1.2 Widening Primitive Conversions
   */
  public int intValue() {
    return (int) value;
  }

  /**
   * Returns the value of this {@code Short} as a {@code long} after
   * a widening primitive conversion.
   *
   * @jls 5.1.2 Widening Primitive Conversions
   */
  public long longValue() {
    return (long) value;
  }

  /**
   * Returns the value of this {@code Short} as a {@code float}
   * after a widening primitive conversion.
   *
   * @jls 5.1.2 Widening Primitive Conversions
   */
  public float floatValue() {
    return (float) value;
  }

  /**
   * Returns the value of this {@code Short} as a {@code double}
   * after a widening primitive conversion.
   *
   * @jls 5.1.2 Widening Primitive Conversions
   */
  public double doubleValue() {
    return (double) value;
  }

  /**
   * Returns a {@code String} object representing this
   * {@code Short}'s value.  The value is converted to signed
   * decimal representation and returned as a string, exactly as if
   * the {@code short} value were given as an argument to the
   * {@link java.lang.Short#toString(short)} method.
   *
   * @return a string representation of the value of this object in base&nbsp;10.
   */
  public String toString() {
    return Integer.toString((int) value);
  }

  /**
   * Returns a hash code for this {@code Short}; equal to the result
   * of invoking {@code intValue()}.
   *
   * @return a hash code value for this {@code Short}
   */
  @Override
  public int hashCode() {
    return Short.hashCode(value);
  }

  /**
   * Returns a hash code for a {@code short} value; compatible with
   * {@code Short.hashCode()}.
   *
   * @param value the value to hash
   * @return a hash code value for a {@code short} value.
   * @since 1.8
   */
  public static int hashCode(short value) {
    return (int) value;
  }

  /**
   * Compares this object to the specified object.  The result is
   * {@code true} if and only if the argument is not
   * {@code null} and is a {@code Short} object that
   * contains the same {@code short} value as this object.
   *
   * @param obj the object to compare with
   * @return {@code true} if the objects are the same; {@code false} otherwise.
   */
  public boolean equals(Object obj) {
    if (obj instanceof Short) {
      return value == ((Short) obj).shortValue();
    }
    return false;
  }

  /**
   * Compares two {@code Short} objects numerically.
   *
   * @param anotherShort the {@code Short} to be compared.
   * @return the value {@code 0} if this {@code Short} is equal to the argument {@code Short}; a
   * value less than {@code 0} if this {@code Short} is numerically less than the argument {@code
   * Short}; and a value greater than {@code 0} if this {@code Short} is numerically greater than
   * the argument {@code Short} (signed comparison).
   * @since 1.2
   */
  public int compareTo(Short anotherShort) {
    return compare(this.value, anotherShort.value);
  }

  /**
   * Compares two {@code short} values numerically.
   * The value returned is identical to what would be returned by:
   * <pre>
   *    Short.valueOf(x).compareTo(Short.valueOf(y))
   * </pre>
   *
   * @param x the first {@code short} to compare
   * @param y the second {@code short} to compare
   * @return the value {@code 0} if {@code x == y}; a value less than {@code 0} if {@code x < y};
   * and a value greater than {@code 0} if {@code x > y}
   * @since 1.7
   */
  public static int compare(short x, short y) {
    return x - y;
  }

  /**
   * The number of bits used to represent a {@code short} value in two's
   * complement binary form.
   *
   * @since 1.5
   */
  public static final int SIZE = 16;

  /**
   * The number of bytes used to represent a {@code short} value in two's
   * complement binary form.
   *
   * @since 1.8
   */
  public static final int BYTES = SIZE / Byte.SIZE;

  /**
   * Returns the value obtained by reversing the order of the bytes in the
   * two's complement representation of the specified {@code short} value.
   *
   * @param i the value whose bytes are to be reversed
   * @return the value obtained by reversing (or, equivalently, swapping) the bytes in the specified
   * {@code short} value.
   * @since 1.5
   */
  public static short reverseBytes(short i) {
    return (short) (((i & 0xFF00) >> 8) | (i << 8));
  }


  /**
   * Converts the argument to an {@code int} by an unsigned
   * conversion.  In an unsigned conversion to an {@code int}, the
   * high-order 16 bits of the {@code int} are zero and the
   * low-order 16 bits are equal to the bits of the {@code short} argument.
   *
   * Consequently, zero and positive {@code short} values are mapped
   * to a numerically equal {@code int} value and negative {@code
   * short} values are mapped to an {@code int} value equal to the
   * input plus 2<sup>16</sup>.
   *
   * @param x the value to convert to an unsigned {@code int}
   * @return the argument converted to {@code int} by an unsigned conversion
   * @since 1.8
   */
  public static int toUnsignedInt(short x) {
    return ((int) x) & 0xffff;
  }

  /**
   * Converts the argument to a {@code long} by an unsigned
   * conversion.  In an unsigned conversion to a {@code long}, the
   * high-order 48 bits of the {@code long} are zero and the
   * low-order 16 bits are equal to the bits of the {@code short} argument.
   *
   * Consequently, zero and positive {@code short} values are mapped
   * to a numerically equal {@code long} value and negative {@code
   * short} values are mapped to a {@code long} value equal to the
   * input plus 2<sup>16</sup>.
   *
   * @param x the value to convert to an unsigned {@code long}
   * @return the argument converted to {@code long} by an unsigned conversion
   * @since 1.8
   */
  public static long toUnsignedLong(short x) {
    return ((long) x) & 0xffffL;
  }

  /**
   * use serialVersionUID from JDK 1.1. for interoperability
   */
  private static final long serialVersionUID = 7515723908773894738L;
}
